Shotshell with integral base wad



Feb. 27, 196s G L. HETER 3,370,534

SHOTSHELL WITH INTEGRAL BASE WAD Filed March 24, 1966 /f/c/ :n I

56.3 li f 25b l \/25 /M/w 70@ 5)/ 650,966 HEAD rf@ 47m/WYE Ys UnitedStates ABSTRACT F THE DISCLOSURE A shotshell casing with integral basewad having a primer cavity with inwardly protecting peripheral sawtoothshaped ribs and an annular shoulder adjacent the flash port formedintegrally of the base wad or on a separate disc.

In the construction of shotshells, a base wad is used inside the head ofthe shotshell to position the propellant charge or powder in front ofthe flashing end of the primer cap. Another function of the base wad isto hold the primer cap in the shotshell and to hold the primer cap insuch a way that the gases generated at detonation do not leak betweenthe primer cap and the base wad. The base wad should also retain theprimer cap in such a way that, after detonation, the base wad andshotshell casing may be reloaded for subsequent use. To achieve thisdesirable feature, and still maintain proper sealing between the baseWad and the primer cap, the base wad must provide for absorption of theforces generated at detonation without becoming cracked or distorted.These forces are particularly great at the surfaces of the base wadwhich are adjacent the primer cap.

With these comments in mind it is to the elimination of these and otherdisadvantages to which the present invention is directed along with theinclusion therein or other novel and desirable features.

An object of my invention is to provide a new and improved base wadintegral with a shotshell of simple and inexpensive construction andoperation.

Another object of my invention is the provision of a base wad, integralwith the shotshell, which base wad seals gases generated upon detonationfrom escaping through the head of the shotshell at the surface ofcontact between the primer cap and the base wad.

Another object of my invention is the provision of an integral base wadand shotshell which, upon detonation of the propellant charge, maintainsa seal and absorbs the pressure generated at detonation withoutdistorting the head of the shotshell or the integral base wad, andwithout cracking or otherwise deforming the base wad.

These and other objects and advantages of my invention will more fullyappear from the following description made in connection with theaccompanying drawings wherein like reference characters refer to thesame or similar parts throughout the several views and in which:

FIG. l is a partial vertical sectional view taken along an axial planeof the shotshell.

FIG. 2 is a partial vertical sectional view taken along an-axial planeof the shotshell at the precise time of detonation.

FIG. 3 is a partial vertical sectional View taken along an axial planeof the shotshell showing an alternate form ofthe integral base wadconstruction.

FIG. 4 is a partial vertical sectional view taken along an axial planeof the shotshell showing an alternate form of the integral base wadconstruction.

i atent ice FIG. 5 is a partial vertical sectional View taken along anaxial plane of the shotshell showing an alternate form of the integralbase wad construction.

FIG. 6 is a partial vertical sectional View taken along an axial planeof the shotshell, showing the integral base wad with a primer capsealing disc disposed thereon.

Referring to FIG. l, a portion of the shotshell is shown and isindicated, in general, by numeral 1t). The shotshell is generallytubular and is formed from compressible, yieldable, resilient plasticmaterial such as polyethylene, and is typically of molded or drawnconstruction. The casing portion is indicated by numeral 11 and; thehead portion by numeral 12. The base wad portion 13 is integral with theshotshell and is located at the head portion thereof. The base wad 13includes a cavity 14 adapted to receive a primer cap. Recess 15 receivesthe ilange of the primer cap, properly seating the primer cap Within thecavity 14. Base wad 13 includes an aperture 16 which interconnects theflashing end of the primer cap with the propellant charge cavity 17.Aperture 16 is of a diameter substantially less than the diameter of theprimer cap. The primer cap receiving cavity 14 includes upwardlyprojecting axial circumferential sealing and cushioning teeth orconvolutions 1S spaced concentrically a predetermined distance apart andadapted to engage the primer cap providing a sealing relation thereto aswell as absorbing the forces generated at detonation. Teeth 18 have agenerally saw-tooth cross-sectional configuration.

The shotshell 1t), in FIG. 2, is shown at the precise time ofdetonation. The forces generated at detonation are absorbed at the basewad. The plastic iiow or deformation is indicated in FIG. 2,particularly at teeth 1S which engage the primer cap, indicated bynumeral 19. The detonation pressures compress the base wad 13 causing apressure seal between teeth 18 and primer cap 19. The plastic iiow tothe teeth and the formation formed thereby is shown in FIG. 2. Thiscontrolled distortion accounts for the sealing and pressure absorbingcharacteristics of my shotshell as generaliy described below. Variationsin the plastic formulation may be used to achieve optimum sealing andpressure absorbing characteristics to arrive at variations in theperformance of the shotshell to give desired characteristics. Primer cap19 is shown disposed in cavity 14 with teeth 18 engaging the surfacesthereof. Primer cap flange 20 is disposed in recess 15, properly seatingthe primer cap within the base wad 13. The Hashing end of the primer capis indicated at 21 with aperture 16 providing communication between theflashing end and the propellant charge 21a. It should be noted that thecircumferential shoulder 2.2, dened by aperture 16, engages the uppersurface of the primer cap at the flashing end 21 thereof. At detonationthe gas pressures force the shoulder 22 into tight sealing relation withprimer cap 19. rThis provides a seal which is greatly increased ineiciency at the time of detonation thereby aiding in preventing gasesgenerated at detonation from escaping through the cavity 14 of the basewad 13. Additional sealing is effected by the pressure absorbing teeth18 since they more tightly engage the primer cap 19 at detonation.Additional sealing is also affected by the action of the primer capflange 20 within recess 15.

Referring to FIG. 3, an alternate embodiment of my linvention is shown.Shotshel-l casing 23 is shown having a primer cap receiving cavity 24with primer cap engaging teeth 25 projecting upwardly. Teeth 25 areformed by a helical thread cutting process, such that teeth 25 arecontinuous. Shotshell 23 is constructed of a yieldable, compressible,resilient plastic material such as polyethylene. Shotshell 23 is ofintegral construction as is shotshell described above. A shoulder 26 isadapted to engage the dashing end of the primer cap providing -a sealingrelation thereto. Aperture 27 is defined by the shoulder 26 and theaperture communicates the propellant charge cavity 28 and the flashingend of the primer cap.

Referring to FIG. 4 another embodiment of my invention is shown. Ashotshell Iis indicated in general by numeral 29. This shotshell is ofthe integral base wad construction described above. Cavity 30 is adaptedto receive a p'rimer cap with teeth 31 in sealing and pressure absorbingrelation thereto. Teeth 31 are concentrically and axially spaced withthe projection substantially outwardiy. Teeth 31 are typically moldedwithin the cavity 30 but may, of course, be cut from the cavity.Shoulder 32 is adapted to seal at the flashing end of the primer anddenes aperture 33 which communicates the ilashing end of the primer capwith the propellant charge cavity 34;

FIG. 5 shows another embodiment of my shotshell with the shotshellindicated, in general, by numeral 35. This is an integral unit includinga base wad, the unit constructed from plastic material similar to theabove units. A primer cap receiving cavity 36 is formed with primer capengaging teeth 37 projecting downwardly. These teeth 37 engage theprimer cap providing a seal thereto, as well as providing pressureabsorbing elements at the time of detonation. Shoulders 38 engage theflashing end of the primer cap and define aperture 39 which communicatesthe propellant charge cavity 4t? with the flashing end of the primercap.

FIG. 6 shows another form of my invention. The shott shell 41 is formedfrom plastic material similar to the material used in forming the abovedescribed shotshells. The base wad is integral with the shotshell andincludes cavity 42 adapted to receive the primer cap. A sealing disc 43having an aperture 44 which communicates the flashing end of the primercap with the propellant charge `4S, is` disposed over the opening orcavity 42 and beneath the powder or propellant charge cavity 45. Theaperture 44 is substantially smaller than the cavity 42 which receivesthe -primer cap. This affords a shoulder portion 46 which engages theprimer cap at detonation, providing a sealing relation thereto. Teeth 47are included to further seal and absorb the pressure forces between thebase wad of the shotshell v41 and the primer cap. Primer cap sealingdisc 43 may be constructed from a compressible, yieldable, resilientplastic such as polyethylene. The sealing disc may also be made fromother plastics and the hardness of the plastic lformulation may bevaried to achieve optimum operating characteristics.

Operation- The operation of my shotshell with the integral base wad isbest described by referring to FIG. 2. At the precise time ofdetonation, base wad 13 is subjected to great pressures exerted by thegases generated by the explosion of the propellant 21a. The pressuresgenerated deform the plastic shotshell 10, causing the plastic to ow andmomentarily deform the wad. Under the inuence of the pressures, theannnlar shoulder 22 is forced generally downwardly into engagingrelation with the ilashing end of the primer cap 19, providing a sealingrelation therewith. At detonation, the base wad is generally compressed,causing the plastic to tiow to the area of the teeth 18 which may deformand compress against the primer cap 19 absorbing the pressure generatedby the explosion. The teeth are momentarily deformed to absorb thepressures and in this deformed position provide an added sealing effectwith respect to the primer cap 19. The primer cap is maintained inposition by the action of the breech bolt thereon at the time of firing.An additional seal is effected between the iiange 20 of the primer cap19 and the wad shoulder above recess 15 which receives ange 20'. Theydeformation of the base Wad 13 results in a considerably more snug fitbetween the flange 20 and the recess 1S, thereby creating additionalsealing between the base wad 13 and the primer cap 19. After detonationhas taken place, the shotshell 10 returns to its normal configuration.Since the shock of the explosion `has been absorbed by the base wad 13,the plastic is neither cracked nor deformed and, consequently, theshotshell 1u may be reused'. This is particularly important to thereloader who finds it etiicient and economical to utilize a shotshellwhich may be reloaded for subsequent use. The shotshell may be reusedwithout any loss of its sealing and shock absorbing characteristics. Forreuse the primer cap 19 is simply removed from the primer cap receivingcavity 14, and a new primer cap inserted. The primer cap snugly engagesAthe teeth 18 and abuts, at the flashing end of the primer cap, theannular shoulder 22.

The alternate forms of my invention utilizes substantially the sameoperation as described above.

4It will, -of course, be understood that various changes may be made inthe form, details, arrangement and proportions of the various partswithout departing from the scope of my invention.

What is claimed is:

1. A plastic shotshell having a generally tubular configuration, saidshotshell comprising,

a generally tubular plastic casing `portion adapted to contain apropellant charge,

a head portion integral with said casing portion,

a plastic base wad integral with said head portion and disposed at oneend thereof, said base wad having a iiat inner surface lfacing inwardlyof the casing portion and also having an axial cavity adapted to receivea primer cap, the axial cavity communicating with said casing portionwhereby the primer cap dashing end contacts the propeliant charge, and

sealing and pressure absorbing elements integral with saidv base wad anddisposed peripherally of and within the primer cap receiving cavity,said sealing and pressure absorbing elements projecting into the cavityand having a sawtooth cross-sectional configuration and adapted toengage the primer cap in sealing and pressure absorbing relationthereto, said sealing elements deforming under the influence ofinsertion of the primer cap an-d additionally deforming under influenceof the detonation of the propellant charge and ow of plastic in the wadand casing portion to effect pressure absorption and sealing.

2. The shotshell of claim 1 and wherein the tooth projecting generallyupwardly in the direction of the propellant charge.

3. The shotshell of claim 1 wherein said sealing and pressure absorbingelements are disposed helically on the periphery of the primer capreceiving cavity.

4. The shotshell of claim 1 wherein said sawtooth shaped sealing-andpressure absorbing elements project generally downwardly of the primercap receiving cavity.

5. The shotshell of claim 1 including,

a transverse primer cap sealing disc having an axial aperture therein,said sealing disc being disposed in said tubular casing portion adjacentsaid head portion whereby the flashing end of the primer cap contactsthe propellant charge and said sealing disc in sealing relation to theprimer cap, the axial aperture superimposed on the primer cap receivingcavity and having a diameter of substantially less than the diameter ofthe primer cap receiving cavity whereby an annular shoulder is definedadapted to engage the primer cap in sealing and pressure absorbingrelation thereto.

(References on following page) References Cited UNITED FOREIGN PATENTSSTATES PATENTS 1,128,191 10/1956 France. 1 140147 2/1957 France.

2 y y litlffsneffl; gZ 731,743 6/1943 Germany, Mayer et al. 102-44 5BENJAMIN A. BORCHELT, Primary Examiner. Comerford 102-44 ROBERT F.STAHL, Examiner.

